B&K 2250 Light Uživatelský manuál stáhnout pdf (Strana 317)

APPENDIX E

Glossary

305

Underrange Immediate underrange indicates that the broadband sound level is below

the lower limit of the Linear Operating Range and is indicated separately for

the two selectable frequency weightings and for the two channels

(Type 2270 only).

Immediate underrange is only indicated on the screen. No underrange

information is saved with the final result of the measurement.

In case of an underrange indication (2-channel measurements, High Range

only), change to Low Range.

The underrange indication is implemented as required by ISO 61672–1:2013

and does not account for the influence of self-generated noise from the

microphone because the specifications for the lower limit of the Linear

Operating Range apply for measurements of electrical signal inserted into

the preamplifier through the applicable input device. This makes the

underrange indication a dubious indicator of the quality of the measurement,

especially on the more sensitive ranges.

Example 1: Und. A – Immediate underrange for the A-weighted levels

Example 2: U1 AC – Immediate underrange in channel 1 for the A- and

C-weighted levels

Frequency weighting as defined in ISO 8041:2005 – used for whole-body

vibration in buildings, all directions

The band-limiting part of the W

filter

Z-weighting: ‘Zero’ frequency weighting is without any frequency weighting, that is,

equivalent to Linear, LIN or FLAT.

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B&K 2250 Light Uživatelský manuál Strana 317